This invention relates to a semiconductor device having a plurality of accumulation electrode layers, an opposed electrode layer, and a dielectric layer interposed between the accumulation electrodes and the opposed electrode layer.
In the manner which will later be described more in detail, a conventional semiconductor device is disclosed in "IEDM Technical Digest 1991, pp. 823-826". This conventional semiconductor device comprises a semiconductor substrate, a first insulator layer on the semiconductor substrate, a plurality of accumulation electrode layers on the first insulator layer, a dielectric layer on the accumulation electrodes and the first insulator layer, and an opposed electrode layer on the dielectric layer.
Inasmuch as the dielectric layer is interposed between two adjacent ones of the accumulation electrode layers, a coupling capacitance value between two adjacent ones of the accumulation electrode layers is large. Consequently, it is assumed that a voltage of one of the accumulation electrode layers changes, voltages of two ones adjacent to the one of the accumulation electrode layers are changed by the voltage of the one of the accumulation electrode layers. As a result, this conventional semiconductor device has a low reliability.